Surface stability and electronic structure of hydrogen-and fluorine-terminated diamond surfaces: A first principles investigation

The effects of fluorine termination on the stability and bonding structure of diamond (111) surfaces were studied using first principles calculations and compared with hydrogen termination by creating mixed F-and H-containing diamond surfaces. Surface F atoms, similar to H, formed sp ³ -type bonding with C atoms, which resulted in a stable 1×1 configuration. The surface phase diagram built showed that the F-terminated surface was more stable in a larger phase space than H termination, because of the formation of strong ionic C-F bonds and the development of attractive forces between large F atoms, resulting in close packing of F atoms. Hence, the F-terminated diamond surface was more chemically inert. A large repulsive force was required to bring two F-terminated surfaces together, because of the negative charge on F atoms, resulting in reduced adhesion tendency between two F-terminated diamond surfaces compared with H-terminated surfaces. © 2009 Materials Research Society.